Answers

If its been in years, it'll have masses of woody roots all over the place by now, very difficult to deal with. Only recourse if you can't dig it all out is to chop it right down to the woody bases and cut or drill into them and apply SBK to the cuts or holes. Note that SBK should not be spilt on the soil or any surrounding plants, and must be used sparingly so as not to contaminate the ground if other plants are present.

Ho Bamboo, it as been in for years, I try and chopped it back everyear I have put roundup on the thing not done much good, and the local garden centre told me to do that so keep having a go at it cheers

Waste of money and energy and time using roundup - that'll kill of any leaves and green stems if you spray them, but is completely ineffective on wood. The SBK I mention is designed for use on woody plant material.

I forgot to say, if you do use SBK in cuts or holes, cover afterwards with something, anything you've got lying about or a sainsbury's carrier if that'll do it. Excluding light and air from the cut, treated surfaces makes it more effective - not to mention you easily find it again if you need to re-treat.